<template>
<div>
    <router-link 
    tag="div" 
    to="/" 
    class="header-abs"
    v-show="showAbs">
        <div class="iconfont header-abs-back">&#xe685;</div>
    </router-link>
    <div 
        class="header-fixed" 
        v-show="!showAbs"
        :style="opacityStyle"
    >
        <router-link to="/">
            <div class="iconfont header-fixed-back">&#xe685;</div>
        </router-link>
        景点详情
    </div>
</div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    heandleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.heandleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.heandleScroll)
  }
}
</script>

<style lang="stylus" scoped>
@import '~@/assets/variable.styl'
.header-abs
    position:absolute
    left: .2rem
    top: .2rem
    width: .8rem
    height: .8rem
    line-height: .8rem
    text-align center
    border-radius .4rem
    background: rgba(0,0,0,.8)
    .header-abs-back
        color: #fff
        font-size .4rem
.header-fixed
    z-index: 5
    position:fixed
    top: 0
    left: 0
    right: 0
    height: $headerHeight
    line-height: $headerHeight
    text-align: center
    color: #fff
    background: $bgColor
    font-size: .32rem
    .header-fixed-back
        position: absolute
        top: 0
        left: 0
        width: .64rem
        text-align center
        font-size: .4rem
        color: #fff


</style>
